You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!

Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.

If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.

Having a problem logging in? Please visit this page to clear all LQ-related cookies.

Introduction to Linux - A Hands on Guide

This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter.
For more advanced trainees it can be a desktop reference, and a collection of the base knowledge needed to proceed with system and network administration. This book contains many real life examples derived from the author's experience as a Linux system and network administrator, trainer and consultant. They hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own.

If you mean the company that gives me access to the Internet here at my office, no. Both my other servers have no problem with email.

This new server is with a company I've not used before. It's possible they're blocking port 25 (and I've asked just in case), but it would be extraordinary if they did given this is a dedicated server and needs to send and receive email.

NOTE: I can "telnet localhost 25" just fine.

It's "telnet 209.190.35.138 25" from another machine (own PC using secureCRT and telnet while logged in to my other web server) that cause the problem.

So it seems to me, the issue mus be around something preventing connections from port 25 from outside the server itself.

And I'm wondering if there's something obvious on the box itself that I've overlooked (e.g. I'm know nothing about iptables, so may have misunderstood what's I'm seeing there).

For example, the line...

REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited

...appears at the bottom of the iptables report when I type "service iptables status" Is this the problem? Baring in mind the file also contains...

That line says that sendmail is only listening on 127.0.0.1. Only connections coming from 127.0.0.1 will be accepted. If send mail was listening for any incoming connection the line would say this:
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN 12666/sendmail: acc

You definitely need to check out your configuration to see what is up.

To test this out further, you say you can telnet localhost 25 just fine, but replace localhost with the IP address of the network adapter.

The top line was what was originally there (with out the dnl # and tailing dnl). I replaced it with the bottom line. I believe if you restart sendmail after that it will compile your sendmail.mc file to the sendmail.cf for you. Or you can do m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf with root privey. Back up your old cf file.

Quote:

It may be my problem isn't a blocked port at all. As of right now, my /etc/resolv.conf file doesn't contain the IPs of my hosting companies nameservers. I suspect that is the main problem.

That wouldn't stop you from at least making an initial connection to port 25.

if m4 is having trouble then the make -C /etc/mail command will fail because it depends on the presence of m4

You can look at /etc/mail/Makefile to see what the make command is doing.

The main problem was /etc/resolv.conf didn't contain the IP addresses of my server's hosting company's nameservers. As a result, Yum wouldn't work.

Yesterday, I managed to find out what the IP addresses are. As soon I entered them in resolv.conf, I was able to use Yum to install sendmail-cf. Then I was able to update sendmail.cf via sendmail.mc as per normal.